The present invention relates to an air cleaning or air treatment apparatus and, more particularly, to an air-cleaning or air-treatment apparatus which is particularly useful for domestic use.
Air pollution is a major environmental problem around the world. Polluted air is a known cause of many chronic diseases which can be hazardous to the young, the old and people suffering from chronic diseases such as heart diseases, allergies or respiratory system disorders. Major pollutants or contaminants of urban and city air include dusts, ashes and particles and gases emitted by vehicles and industry. Pollens, ashes and dusts are the major pollutants of country air. In order to reduce airborne pollutant levels and to improve indoor air quality, air treatment apparatuses, which are equally known as air purifiers, air cleaners and air filters, are frequently deployed in homes, offices, schools, halls and other establishments to improve air quality.
Solid state mesh or grille type filters are commonly used in conventional air cleaners to remove granulate, particulate or other pollutants from air. These type of filters usually include an assembly of filtering screens on each of which there are closely disposed a large number of very fine and tiny apertures. High efficiency particulate air filters (xe2x80x9cHepa filtersxe2x80x9d) are probably the most well-known type of conventional filters which have a minimum particle removal efficiency of 99.97 percent. Conventional filters usually operate by the physical blocking of airborne air particles.
Hence, it will follow in general that air filters having microscopic apertures are required to block off microscope or tiny particulate pollutants. However, conventional solid state filters having very fine or tiny filter apertures are prone to clogging which means frequent maintenance, servicing or cleaning of the filter elements is required in order to provide continuous optimal operations. Furthermore, conventional air filters remove particles and other pollutants by forcing an incoming air stream through the very fine apertures which are usually densely disposed on the filtering element. The total air-flow rate is therefore dependent on and proportional to the aggregate of the area of the fine apertures on the filtering elements. To increase the air-flow rate, filter elements have been made into various shapes and configurations, for example, shapes resembling the expandable bellow of a hand-held organ or by including a large number of fin shaped filtering elements, to increase the total filtering surface which is inserted between the air-inlets and air-outlets.
However, because of the inherent nature of conventional filters that the filtering surface must be inserted between the air-inlets and the air-outlets to block the incoming air stream so that the incoming air stream has to pass through the filtering elements before reaching the air-outlets to achieve optimal filtering, there is an inherent limit of the maximum blocking surface which can be provided for a given cross-sectional area between the air-inlets and the air-outlets. Additionally, the need to draw air through such filters increases the size and cost of the motor due to the load placed on the system by the filter itself. In addition, filtering elements having a lot of closely packed surfaces, as in the case of the bellow- or fin-type elements, are more prone to clogging and are more difficult to clean since the clogging particles are difficult to remove. Such filtering elements would therefore have shorter mean-time between service or replacement and are therefore not convenient or economical. It is therefore desirable if air cleaners having filter elements of a design which will substantially alleviate the known short-comings associated with conventional filter elements can be provided.
It is therefore an object of the present invention to provide air cleaners which are equipped with filtering means which substantially alleviate the short-comings associated with the afore-said filtering elements used in conventional air filters. It is also an object of the present invention to provide an air filtering system for use in air-cleaners in which the surface area which needs to be clean for the removal of particles clogging the filtering apertures is significantly less than the effective pollutant blocking surface area of the filtering system. Furthermore, it is also an object of the present invention to provide a useful alternative or choice of an air cleaner or an air filtering system for an air-cleaner to the general public.
According to the present invention, there is provided an air cleaning apparatus including an air-inlet, an air-outlet, an air-cleaning means, a compartment inside which there is disposed an air channel joining said air-inlet and said air-outlet, and an air-drawing device drawing air into said compartment, wherein said air channel is adapted to cause an air stream coming into said compartment through said air-inlet to flow substantially only along said air-channel towards said air outlet and said air-cleaning means includes a fluid curtain disposed at least along a part of said air-channel.